Heat development image forming process thermally decoloring image recording process and process for decoloring cyanine dye

Abstract

A heat developable light-sensitive material comprises a support, a light-sensitive layer and a non-light-sensitive layer. The light-sensitive layer contains silver halide and a reducing agent. The non-light-sensitive layer contains a cyanine dye represented by the formula (I) or a salt thereof and a base precursor: in which R 1 is hydrogen, an aliphatic group, an aromatic group, —NR 21 R 24 , —OR 21 or —SR 21 , each of R 21 and R 24 independently is hydrogen, an aliphatic group or an aromatic group, or R 21 and R 24 are combined to form a nitrogen-containing heterocyclic ring; R 2 is hydrogen, an aliphatic group or an aromatic group; R 3 is an aliphatic group; L 1 is a methine chain consisting of an odd number of methines; and each of Z 1 and Z 2 independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring. A heat development image forming process, a thermal image recording material, a thermally decoloring image recording process and a process for decoloring a cyanine dye are also disclosed.

What is claimed is:  
     
       1. A heat developable light-sensitive material comprising a support, a light-sensitive layer and a non-light-sensitive layer, said light-sensitive layer containing silver halide and a reducing agent, and said non-light-sensitive layer containing a cyanine dye represented by the formula (I-1) or a salt thereof and a base precursor, wherein the cyanine dye or the salt thereof is in the form of solid particles, which are dispersed in the non-light-sensitive layer:                    
       in which R 1  is hydrogen, an aliphatic group, an aromatic group, —NR 21 R 24 , —OR 21  or —SR 21 , each of R 21  and R 24  independently is hydrogen, an aliphatic group or an aromatic group, or R 21  and R 24  are combined to form a nitrogen-containing heterocyclic ring; R 2  is hydrogen, an aliphatic group or an aromatic group; R 3  is an aliphatic group; L 1  is a trimethine or a pentamethine; and each of Z 1  and Z 2  independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring. 
     
     
       2. The heat developable light-sensitive material as claimed in claim  1 , wherein R 1  in the formula (I-1) is —NR 21 R 24 , —OR 21  or—SR 21 . 
     
     
       3. The heat developable light-sensitive material as claimed in claim  1 , wherein the cyanine dye is represented by the formula (Ia-1):                    
       in which R 11  is hydrogen, an aliphatic group, an aromatic group, —NR 31 R 34 , —OR 31  or —SR 31 , each of R 31  and R 34  independently is hydrogen, an aliphatic group or an aromatic group, or R 31  and R 34  are combined to form a nitrogen-containing heterocyclic ring; R 12  is hydrogen, an aliphatic group or an aromatic group; R 13  is an aliphatic group; L 11  is a trimethine or a pentamethine; each of Y 11  and Y 12  independently is —CR 14 R 15 —, —NR 14 —, —O—, —S— or —Se—, each of R 14  and R 15  independently is hydrogen or an aliphatic group or R 14  and R 15  are combined to form an aliphatic ring; and the benzene rings of Z 11  and Z 12  may be condensed with another benzene ring. 
     
     
       4. The heat developable light-sensitive material as claimed in claim  3 , wherein R 11  in the formula (Ia-1) is —NR 31 R 34 , —OR 31  or —SR 31 . 
     
     
       5. The heat developable light-sensitive material as claimed in claim  1 , wherein the cyanine dye represented by the formula (I-1) is represented by the formula (Ib):                    
       in which the two groups of R 41  are identical, and R 41  is hydrogen, an aliphatic group, an aromatic group, —NR 51 R 52 , —OR 51  or —SR 51 ; each of R 51  and R 52  independently is hydrogen, an aliphatic group or an aromatic group, or R 51  and R 52  are combined to form a nitrogen-containing heterocyclic ring. 
     
     
       6. A heat development image forming process comprising steps of: 
       imagewise exposing to light a heat developable light-sensitive material comprising a support, a light-sensitive layer and a non-light-sensitive layer, said light-sensitive layer containing silver halide and a reducing agent, and said non-light-sensitive layer containing a cyanine dye represented by the formula (I-1) or a salt thereof and a base precursor, wherein the cyanine dye or the salt thereof is in the form of solid particles, which are dispersed in the non-light-sensitive layer:                    
       in which R 1  is hydrogen, an aliphatic group, an aromatic group, —NR 21 R 24 , —OR 21  or —SR 21 , each of R 21  and R 24  independently is hydrogen, an aliphatic group or an aromatic group, or R 21  and R 24  are combined to form a nitrogen-containing heterocyclic ring; R 2  is hydrogen, an aliphatic group or an aromatic group; R 3  is an aliphatic group; L 1  is a trimethine or a pentamethine; and each of Z 1  and Z 2  independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring; and then heating the heat developable light-sensitive material at 80 to 200° C. to form a base from the base precursor whereby the cyanine dye is decolored and to develop the silver halide. 
     
     
       7. The heat development image forming process as claimed in claim  6 , wherein R 1  in the formula (I-1) is —NR 21 R 24 , —OR 21  or —SR 21 . 
     
     
       8. The heat development image forming process as claimed in claim  6 , wherein the cyanine dye is represented by the formula (Ia-1):                    
       in which R 11  is hydrogen, an aliphatic group, an aromatic group, —NR 31 R 34 , —OR 31  or —SR 31 , each of R 31  and R 34  independently is hydrogen, an aliphatic group or an aromatic group, or R 31  and R 34  are combined to form a nitrogen-containing heterocyclic ring; R 12  is hydrogen, an aliphatic group or an aromatic group; R 13  is an aliphatic group; L 11  is a trimethine or a pentamethine; each of Y  11  and Y 12  independently is —CR 14 R 15 —, —NR 14 —, —O—, —S— or —Se—, each of R 14  and R 15  independently is hydrogen or an aliphatic group or R 14  and R 15  are combined to form an aliphatic ring; and the benzene rings of Z 11  and Z 12  may be condensed with another benzene ring. 
     
     
       9. The heat development image forming process as claimed in claim  8 , wherein R 11  in the formula (Ia-1) is —NR 31 R 34 , —OR 31  or —SR 31 . 
     
     
       10. The heat development image forming process as claimed in claim  6 , wherein the cyanine dye represented by the formula (I-1) is represented by the formula (Ib):                    
       in which the two groups of R 41  are identical, and R 41  is hydrogen, an aliphatic group, an aromatic group, —NR 51 R 52 , —OR 51  or —SR 51 ; each of R 51  and R 52  independently is hydrogen, an aliphatic group or an aromatic group, or R 51  and R 52  are combined to form a nitrogen-containing heterocyclic ring. 
     
     
       11. A thermal image recording material comprising a support and an image recording layer, said image recording layer containing a cyanine dye represented by the formula (I-1) or a salt thereof and a base precursor, wherein the cyanine dye or the salt thereof is in the form of solid particles, which are dispersed in the image recording layer:                    
       in which R 1  is hydrogen, an aliphatic group, an aromatic group, —NR 21 R 24 , —OR 21  or —SR 21 , each of R 21  and R 24  independently is hydrogen, an aliphatic group or an aromatic group, or R 21  and R 24  are combined to form a nitrogen-containing heterocyclic ring; R 2  is hydrogen, an aliphatic group or an aromatic group; R 3  is an aliphatic group; L 1  is a trimethine chain or a pentamethine chain; and each of Z 1  and Z 2  independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring. 
     
     
       12. The thermal image recording material as claimed in claim  11 , wherein the cyanine dye represented by the formula (I-1) is represented by the formula (Ib):                    
       in which the two groups of R 41  are identical, and R 41  is hydrogen, an aliphatic group, an aromatic group, —NR 51 R 52 , —OR 51  or —SR 51 ; each of R 51  and R 52  independently is hydrogen, an aliphatic group or an aromatic group, or R 51  and R 52  are combined to form a nitrogen-containing heterocyclic ring. 
     
     
       13. A thermally decoloring image recording process comprising imagewise heating a thermal image recording material at 80 to 200° C., said image recording material comprising a support and an image recording layer, said image recording layer containing a cyanine dye represented by the formula (I-1) or a salt thereof and a base precursor, wherein the cyanine dye or the salt thereof is in the form of solid particles, which are dispersed in the image recording layer:                    
       in which R 1  is hydrogen, an aliphatic group, an aromatic group, —NR 21 R 24 , —OR 21  or —SR 21 , each of R 21  and R 24  independently is hydrogen, an aliphatic group or an aromatic group, or R 21 , and R 24  are combined to form a nitrogen-containing heterocyclic ring; R 2  is hydrogen, an aliphatic group or an aromatic group; R 3  is an aliphatic group; L 1  a trimethine chain or a pentamethine chain; and each of Z 1  and Z 2  independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring; to form a base from the base precursor whereby the cyanine dye is decolored. 
     
     
       14. The thermally decoloring image recording process as claimed in claim  13 , wherein the cyanine dye represented by the formula (I-1) is represented by the formula (Ib):                    
       in which the two groups of R 41  are identical, and R 41  is hydrogen, an aliphatic group, an aromatic group, —NR 51 R 52 , —OR 51  or —SR 51 ; each of R 51  and R 52  independently is hydrogen, an aliphatic group or an aromatic group, or R 51  and R 52  are combined to form a nitrogen-containing heterocyclic ring. 
     
     
       15. A process for decoloring a cyanine dye comprising heating a cyanine dye represented by the formula (II-1) or a salt thereof at 80 to 200° C. in the presence of a base:                    
       in which X 21  is —NR 24 —, —O— or —S—; each of R 21  and R 24  independently is hydrogen, an aliphatic group or an aromatic group, or R 21  and R 24  are combined to form a nitrogen-containing heterocyclic ring; R 22  is hydrogen, an aliphatic group or an aromatic group; R 23  is an aliphatic group; L 21  is a trimethine chain or a pentamethine chain; and each of Z 21  and Z 22  independently is an atomic group forming a five-membered or six-membered nitrogen-containing heterocyclic ring, which may be condensed with an aromatic ring. 
     
     
       16. The process for decoloring a cyanine dye as claimed in claim  15 , wherein the cyanine dye represented by the formula (II-1) is represented by the formula (IIa-1):                    
       in which X 31  is —NR 34 —, —O— or —S—; each of R 31  and R 34  independently is hydrogen, an aliphatic group or an aromatic group, or R 31  and R 34  are combined to form a nitrogen-containing heterocyclic ring; R 32  is hydrogen, an aliphatic group or an aromatic group; R 33  is an aliphatic group; L 31  is a trimethine chain or a pentamethine chain; Y 31  and Y 32  independently is —CR 37 R 38 —, —NR 37 —, —O—, —S— or —Se—, each of R 37  and R 38  independently is hydrogen or an aliphatic group or R 37  and R 38  are combined to form an aliphatic ring; and the benzene rings of Z 31  and Z 32  may be condensed with another benzene ring.